Paleontologists have discovered protein sequences in dense enameled fabrics of ancient rhinoceroid and proboscidian fossils collected on Buluk and Loperot sites in the Turkana basin, in Kenya.
The Turkana basin within the East African Rift System preserves fossil assemblies which date back to more than 66 million years; Green and al. Powdered samples have collected a paleoproteomic analysis from the dense interiors of the enamel of the great herbivores from the beginning of the Pleistocene to the Oligocene (29 million years). Image credit: green and al., Two: 10.1038 / S41586-025-09040-9.
“The teeth are rocks in our mouths,” said Dr. Daniel Green, researcher at Harvard University and Columbia University.
“These are the most difficult structures that all animals do, so you can find a tooth of one hundred or a hundred million years, and it will contain a geochemical recording of the animal’s life.”
“This includes what the animal has eaten and drank, as well as its environment.”
“In the past, we thought that the mature enamel, the most difficult part of the teeth, should really be very little protein.”
However, using a new, more recent proteomics technique called mass spectrometry in liquid chromatography tandem (LC-MS / MS), the authors were able to detect a large diversity of proteins in different biological tissues.
“The technique involves several stages where peptides are separated according to their size or chemistry so that they can be analyzed sequentially to higher resolutions than what was possible with previous methods,” said Dr. Kevin Uno, also from Harvard University and Columbia University.
“We and other researchers recently found that there were dozens – if not even hundreds – of different types of proteins present inside the dental enamel,” said Dr. Green.
With the awareness that many proteins are in contemporary teeth, researchers have turned to rhinosides and proboscidian fossils.
As herbivores, these animals had big teeth to crush their plant diet.
“These mammals may have two to three millimeters thick enamel. It was a lot of equipment to work with,” said Dr. Green.
“What we have found – fragments of peptides, amino acid chains, which together form proteins as old as 18 million years – has changed on the ground.”
“No one has ever found any peptide fragments that are so old before.”
Until now, the oldest published materials have been around 3.5 million years.
“Newly discovered peptides cover a range of proteins that fulfill different functions, fully known as proteome,” said Dr. Green.
“One of the reasons why we are delighted with these old teeth is that we do not have the complete protein of all the proteins that could have been found inside the body of these ancient elephants or rhinos, but we have a group.”
“With such a collection, there could be more information available from a group of them than one protein in itself.”
“This research opens up new borders in paleobiology, allowing scientists to go beyond bones and morphology to rebuild molecular and physiological features of extinguished animals and homes,” said Dr. Emmanuel Ndiema, researcher at the National Museum of Kenya.
“We can use these fragments of peptides to explore the relationships between ancient animals, similar to the way modern DNA in humans is used to identify the way people are linked to each other.”
“Even if an animal is completely extinguished – and we have animals that we analyze in our study which do not have living descendants – you can always, in theory, extract proteins from their teeth and try to place them on a phylogenetic tree,” said Dr. Green.
“Such information could be able to resolve long -standing debates between paleontologists on the other mammals lines. These animals are linked to the use of molecular evidence. “
The results appear today in the newspaper Nature.
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Dr Green and al. Eighteen million years of various enamel proteome from the East African Rift. Naturepublished online on July 9, 2025; DOI: 10.1038 / S41586-025-09040-9
